Both cancer patients and their family caregivers are at risk for developing chronic diseases earlier and more frequently than those who have not been affected by cancer.1, 2 With the numbers of cancer survivors rising, health decline in this population becomes a substantial concern to both affected families and to society. Elevated inflammation is one potent marker of chronic disease development in both cancer survivors and their family caregivers.22,24,28-33 Thus, identifying risk factors for elevated inflammation in cancer patients and caregivers will provide targets for assessment and intervention to improve cancer patient and caregiver long- term health and reduce their risk for premature frailty and mortality. Depression is a known predictor of proinflammatory markers in both cancer patients36,37 and healthy persons.38- 40 However, the association between depressive symptoms and inflammation has yet to be studied in patients and caregivers of colorectal cancer, the third most common cancer in both men and women. Additionally, it is known patients and caregivers mutually influence each other's health outcomes, but the dyadic impacts of one's depressive symptoms on the others' inflammation have yet to be studied. This proposed study will investigate the relations between depressive symptoms as a psychological risk factor for elevated proinflammatory markers interleukin (IL)-6 and C-reactive protein (CRP). These relations will be studied in colorectal cancer patients alone, their family caregivers alone, and the patients and caregivers together. Depressive symptoms will be assessed using the CES-D at two months post-diagnosis; pro- inflammatory cytokines will be measured at 11 months post-diagnosis. Actor-partner interdependence modeling will be used to analyze data from a subset of 100 patient-caregiver dyads from an ongoing funded project. Proposed training plans to achieve the study aims include gaining comprehensive knowledge in theories and analytic strategies involved in dyadic research through close didadic training by the sponsor, supplemental coursework, exposure to national behavioral medicine conferences, manuscript preparation, and presentations. This training will facilitate the applicant's career goal of independent clinical research specializing in identifying modifiable psychological risk factors for health decline in cancer patients and caregivers. As depressive symptoms can be detected through low-cost, brief screening methods and can be effectively treated, if the data from this study show promise that both patient and caregiver depressive symptoms at diagnosis have direct, long-term immunological consequences for themselves and their partners, findings would offer a novel, cost-efficient primary and tertiary chronic disease prevention target.